Hydrogen bonding of benzoic acid esters to unesterified hydroxyl groups in nitrocellulose

1975 ◽  
Vol 19 (10) ◽  
pp. 2913-2915
Author(s):  
B. W. Brodman ◽  
M. P. Devine ◽  
M. T. Gurbarg
Keyword(s):  
Hydrogen Bonding ◽  
Benzoic Acid ◽  
Hydroxyl Groups ◽  
Acid Esters

Enantioselective Nucleophilic Aromatic Substitution Reaction of Azlactones to Synthesize Quaternary α-Amino Acid Derivatives

Synlett ◽  
2020 ◽  
Author(s):  
Xiaohua Liu ◽  
Yi Li ◽  
Hao Pan ◽  
Wang-Yuren Li ◽  
Xiaoming Feng
Keyword(s):  
Hydrogen Bonding ◽  
Charge Transfer ◽  
Amino Acid ◽  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Amino Acid Derivatives ◽  
Amino Acid Esters ◽  
Aromatic Substitution ◽  
Charge Transfer Interaction ◽  
Acid Esters

AbstractAn asymmetric organocatalytic nucleophilic aromatic substitution reaction of azlactones with electron-deficient aryls was established. A variety of α-aryl α-alkyl α-amino acid esters and peptides were obtained in decent yields and stereoselectivities. A new bifunctional catalytic mode involving charge-transfer interaction and hydrogen bonding is proposed to explain the enantioselectivity.

Substitutional and solvation effects on conformational equilibria. Effects on the interaction between opposing axial oxygen atoms

1969 ◽  
Vol 47 (23) ◽  
pp. 4441-4446 ◽  
Author(s):  
R. U. Lemieux ◽  
A. A. Pavia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Hydroxyl Groups ◽  
Evidence Based ◽  
Electrostatic Repulsion ◽  
Hydrogen Bridge ◽  
Conformational Equilibria ◽  
Free Hydroxyl ◽  
Oxygen Atoms

Evidence based both on nuclear magnetic resonance and rotation data primarily obtained from methyl 3-deoxy-β-L-erythro-pentopyranoside and a number of its derivatives is interpreted to show that the electrostatic repulsion between the oxygen atoms at the 2 and 4 positions is substantially less when these oxygens are linked to acyl groups than when in the form of either methyl ethers or as hydroxyl groups hydrogen bonded to solvent. Also, experimental evidence is presented which requires the hydrogen bridge between two axially disposed hydroxyl groups to be substantially strengthened by hydrogen bonding of the free hydroxyl by solvent.

Reactivity of α-amino acids in the N-acylation with benzoic acid esters in aqueous dioxane

2010 ◽  
Vol 80 (5) ◽  
pp. 964-967 ◽  
Author(s):  
N. R. Ishkulova ◽  
L. E. Oparina ◽  
L. B. Kochetova ◽  
T. P. Kustova ◽  
N. V. Kalinina ◽  
...  
Keyword(s):  
Amino Acids ◽  
Benzoic Acid ◽  
Aqueous Dioxane ◽  
Acid Esters

Proton spin–spin coupling constants and intramolecular hydrogen bonding in bromine derivatives of 1,3-dihydroxybenzene

1976 ◽  
Vol 54 (14) ◽  
pp. 2228-2230 ◽  
Author(s):  
Ted Schaefer ◽  
J. Brian Rowbotham
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Derivatives Of

The conformational preferences in CCl4 solution at 32 °C of the hydroxyl groups in bromine derivatives of 1,3-dihydroxybenzene are deduced from the long-range spin–spin coupling constants between hydroxyl protons and ring protons over five bonds. Two hydroxyl groups hydrogen bond to the same bromine substituent in 2-bromo-1,3-dihydroxybenzene but prefer to hydrogen bond to different bromine substituents when available, as in 2,4-dibromo-1,3-dihydroxybenzene. When the OH groups can each choose between two ortho bromine atoms, as in 2,4,6-tribromoresorcinol, they apparently do so in a very nearly statistical manner except that they avoid hydrogen bonding to the common bromine atom.

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